کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5888799 1568129 2016 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Regional differences in oxidative metabolism and mitochondrial activity among cortical bone osteocytes
ترجمه فارسی عنوان
تفاوت های منطقه ای در متابولیسم اکسیداتیو و فعالیت های میتوکندری در استئوسیت های استخوان کورتنی
کلمات کلیدی
استئوسیت ها، متابولیسم اکسیداتیو، عملکرد میتوکندری، تصویربرداری در محل، میکروسکوپ چند فتونی، استخوان کورتیک،
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شناسی تکاملی
چکیده انگلیسی
Metabolic oxidative stress has been implicated as a cause of osteocyte apoptosis, an essential step in triggering bone remodeling. However, little is known about the oxidative behavior of osteocytes in vivo. We assessed the redox status and distribution of total and active mitochondria in osteocytes of mouse metatarsal cortical bone in situ. Multiphoton microscopy (MPM) was used to measure fluorescence of reduced pyridine nucleotides (NADH) under normoxic conditions and acutely following extreme (postmortem) hypoxic stress. Under non-hypoxic conditions, osteocytes exhibited no detectable fluorescence, indicating rapid NADH re-oxidation. With hypoxia, NADH levels peaked and returned to near baseline levels over 3 h. Cells near the periosteal surface reached maximum NADH levels twice as rapidly as osteocytes near the mid-cortex, due to the time required to initiate NADH accumulation; once started, NADH accumulation followed a similar exponential relationship at all sites. Osteocytes near periosteal and endosteal bone surfaces also had higher mitochondrial content than those in mid-cortex based on immunohistochemical staining for mitochondrial ATPase-5A (Complex V ATPase). The content of active mitochondria, assessed in situ using the potentiometric dye TMRM, was also high in osteocytes near periosteum, but low in osteocytes near endocortical surfaces, similar to levels in mid-cortex. These results demonstrate that cortical osteocytes maintain normal oxidative status utilizing mainly aerobic (mitochondrial) pathways but respond to hypoxic stress differently depending on their location in the cortex, a difference linked to mitochondrial content. An apparently high proportion of poorly functional mitochondria in osteocytes near endocortical surfaces, where increased apoptosis mainly occurs in response to bone remodeling stimuli, further suggest that regional differences in oxidative function may in part determine osteocyte susceptibility to undergo apoptosis in response to stimuli that trigger bone remodeling.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Bone - Volume 90, September 2016, Pages 15-22
نویسندگان
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